Internal combustion engines



United States Patent "ice 3,150,647 INTERNAL COMBUSTION ENGINES Gus Schreiher, 4217 Herschel, Dallas, Tex. Filed Nov. 4, 1963, Ser. No. 320,978 1 Claim. (63!. 123-48) My invention consists of an accessory cylinder containing a hydraulically operated control piston, the crown of this control piston forming part of the wall of the combustion chamber. One such mechanism is necessary for each cylinder of a multi-cylindered reciprocating piston internal combustion engine. This control piston in the accessory cylinder has as its function the control of the volume of the combustion chamber so that within the mechanical limits of the device this piston maintains a desired constant peak combustion pressure irregardless of the onset pressure.

In the case of spark ignition engines the purpose of such a constant peak combustion pressure is to maintain as high a peak compression pressure as is possible cornpatible with the grade of gasoline being utilized. It is generally recognized that the combustion pressure of an operating engine is 4.25 times greater than that of the compression pressure, hence the higher the compression pressure, the higher the combusion pressure and the taller the positive work loop of intracylinder pressure and of net crankshaft torque. Calculations made through 15 of compression and combustion of an engine with a constant peak combustion pressure of optimal height will, with an onset pressure of 4 p.s.i.a., yield a net increase of 62% of torque output over the net torque output of a standard fixed volume engine with a compression ratio of 8 with the same onset pressure of 4 p.s.i.a. This is possible because it is not the compression ratio per se which causes or does not cause detonation of gasoline-air mixtures, but detonation occurs or does not occur depending upon the temperature reached by the remaining unburned charge as the flame front advances from the sparkplug to the opposite side of the cylinder wall.

The hydraulic control of the accessory piston is based upon the physical fact that engine lubricating oil in minimally compressible and minimally expansible, hence for practical purposes may be considered both incompressible and non-expansible. Distal to the control piston in the accessory cylinder there is provided a closed space which is filled with engine lubricating oil, this space having only three apertures. The control piston with its sealing rings forming the closure of the main aperture, the cylinder itself. A pressure relief valve closes the second aperture, this aperture being of moderate size to allow high capacity flow. The third aperture consists of the oil inlet orifice which is of minimal size and provided with a check valve which prohibits the exit of the oil from this sealed chamber by means of this orifice.

By this construction the oil entering the hydraulic chamber has a one-way entrance through the check valveequipped inlet orifice and only a one-way exit through the pressure relief valve. However it is to be expected that with peak combustion pressures of 800 to 1000 p.s.i. that some oil will escape past the retaining ring or rings of the control piston allowing some outward movement of the control piston during combustion. However some degree of oscillation is beneficial to prevent the rings of the control piston from becoming adherent to its surrounding Walls of the accessory cylinder. The oil entrance should permit enough oil to enter during intake and exhaust to allow for this leakage plus an additional several drops of oil volume to enter this closed hydraulic chamber.

As a result of such a construction, the control piston is slightly pushed toward the combustion chamber during intake and exhaust by the increase in volume of the hydraulic chamber because of the incoming oil. However,

3,150,647 Patented Sept. 29., 1964 during compression and combustion the control piston is essentially immobile except for the minute movement due to the compression of the lubricating oil and the oil lost past the sealing ring of the control pistonunless the pressure relief valve yields and permits a decrease in volume of the oil in the hydraulic chamber, thereby permitting the control piston to move away from the combustion chamber.

To summarize, with the onset pressure in a steady state, the control piston oscillates minimally; when the onset pressure is increased the control piston recedes, rapidly if need be, away from the combustion chamber decreasing the compression ratio until a steady state is again resumed; and when the onset pressure is reduced the control piston gradually moves toward the combustion chamber increasing the compression ratio until a steady state is 'again resumed.

The constant peak combustion pressure which this mechanism produces causes a torsional vibration such as now occurs at full throttle operation in conventional fixed volume engines but this is a minor consideration consider ing the enhanced efiiciency which this mechanism produces at part throttle operationthe usual running state of most spark ignition engines.

This mechanism, when designed to provide a low compression ratio, permits of the inefficient use of multiple carburetors or of a supercharger-yet produces the same elevated efficiency of part throttle operation. Because of this fact such a mechanism should be invaluable in internal combustion airplane engines which utilize superchargers.

This mechanism also has usefulness in compression ignition engines which have an air throttle by maintaining a high compression temperature even though the volume of fuel and the volume of the air intake (onset pressure) both be reduced.

In the illustration my mechanism is shown as utilizing a hydraulic pressure relief valve and provides a lubrication system for the control piston which also serves to separate the oil leakage and combustion chamber blowby from each other.

As illustrated in the figure my mechanism is shown as part of the cylinder head but it does not necessarily have to be so positioned. The block cylinder 1 connects by an adequate opening to the lower portion of the accessory cylinder 2 which forms a portion of the combustion chamber. The accessory (or control) piston 3 is shown in cross-section filled with insulating material to force the flow of heat to the periphery for conduction to the waterjacketed walls of the accessory cylinder 2.

In the illustration the enclosed hydraulic chamber is shown above the accessory or control piston 3. This hydraulic space is formed within cylinder 2 by the piston 3 and by a cylindrical cap 5. The only remaining openings of this hydraulic chamber are the inlet orifice 11 with its check-valve 9 and passageway 13 produced when the piston 12 of the hydraulic pressure relief valve yields over the high capacity outlet orifice. The capacity of the inlet orifice 11, its check-Valve 9, and its passageway 7 must be slightly greater than any volume of oil which might leak past the sealing ring or rings of controlpiston 3 after maximal wear from usage has occurred. By such a mechanism the hydraulic chamber enhances its volume during each intake and exhaust stroke while the combustion chamber is inversely reduced in volume. Then during compression and combustion the hydraulic chamber is reduced in volume if the pressure relief valve yields, otherwise no appreciable, reduction in volume of the hydraulic chamber occurs except for the amount of lubricating oil which has leaked past the sealing ring or rings of piston 3. By this mechanism the control piston oscillates minimally at a constant onset pressure, gradually moves toward the combustion chamber if the onset pressure is reduced, and rapidly, if necessary, moves away from the combustion chamber if the onset pressure is increased.

The design of the hydraulic relief valve is of particular importance. The purpose of this valve is to produce exactly the same peak combustion pressure in each cylinder of a multi-cylindered engine as well as to eliminate the need of large spring-actuated relief valves. To eliminate the need of a hydraulic intensifier or of a high pressure oil compressor pump this hydraulic relief valve is designed to have a much larger upper surface for the application of ordinary oil pump pressures than the surface covering the outlet orifice of the hydraulic chamber. Thusly, if the engine oil pump is regulated to produce 50 p.s.i. pressure and the peak combustion pressure desired is 1000 p.s.i., the upper surface of piston 12 of the pressure relief valve should be 20 times the surface area of the escape orifice. This design in effect serves as a hydraulic intensifier. In the illustration the engine oil enters through orifice 4, fills the cylinder 5 of the pressure relief valve and pushes against the upper surface of the pressure relief valve piston 12. A dash-pot 6 is provided to prevent any striking of metal parts when the engine is started (at which time no oil pressure exists). The piston 12 approximates a diaphragm in shape and utilizes a guide 19 to maintain a true alignment within its cylinder 5. Oil which escapes past the piston 12 and which is released by the pressure relief valve through passageway 13 returns to the oil pan by orifice 14.

The upper surface of the control piston 3 (which is opposite the crown) is provided with a recessed area 19 to prevent this portion of piston 3 from striking the portion of piston 12 which furnished the oil inlet 11. This same upper surface of piston 3 is provided with a flange 17 which, in combination with a recession in the cap of the hydraulic chamber, and a rim 18 in the accessory cylinder 2 provides a dash-pot at each end of the direction of movement of the control piston 3. Such a construction not only serves to prevent metal clashing but also limits the movement of the control piston toward the combustion chamber. Water jackets 16 are provided for cooling of the accessory cylinder 2 and its control piston 3.

The two sets of rings of the control piston 3 are provided with a unique lubrication system, this system also serving the additional dual function of preventing the leaking oil from the hydraulic chamber from entering the combustion chamber and of simultaneously preventing the blowby gases from the combustion chamber from entering the hydraulic chamber. This is accomplished by a recession 21 in piston 3 with engine lubricating oil entering this recessed area through the cylinder 2 wall via a small orifice 20 and draining to the oil pan of the engine through a patent opening 23. With such a design there is no appreciable pressure present within the recessed space 21 thereby facilitating the drainage of both lubricating oil and blowby gases to the oil pan of the engine.

An orifice 8 is provided in the wall of the combustion chamber for the placement of a spark plug or fuel injector as the case may be. Sealing gaskets 25 are noted to detail the method of assembly of the mechanism, the control piston being placed in the accessory cylinder 2 from above as illustrated.

It will be noted that this design places the spark plug to one side of a non-spherical combustion chamber. It is generally recognized that during the compression stroke such a side chamber location serves as a swirl chamber for cleansing the spark plug of gases which remain from the previous combustion. It is also generally recognized that such a non-spherical combustion chamber (by loss of heat to the surrounding closely approximated walls with a large surface area to volume ratio) allows a high combustion pressure with less heat reaching the unburned charge on the far side of the combustion chamber. This reduction in heat to this unburned charge reduces the tendency for detonation to occur. Since this combustion chamber will have more volume in relation to its surface area (will be more spherical) with a high onset pressure detonation will be more likely to occur with such a high onset pressure rather than with a low onset pressure, even with the same peak combustion pressure produced by this mechanism.

In the case of spark ignition engines, because the engine oil pressure itself controls the peak combustion pressure in this presently described hydraulic pressure relief valve system, if provision is made for operator or mechanic control of the engine oil pump pressure (by means of regulating the force applied by the spring of the engine oil pump against its own escape orifice) maximal utilization may be obtained from whatever grade of fuel is purchased by the operator. In practical operation this would mean that the operator would reduce the engine oil pressure to just below that pressure which causes the engine to detonate at low rpm. and full throttle operation. By such a procedure the full benefits of the high ignition temperature of premium fuels (which permit higher and more efficient combustion pressures) would be constantly utilizedeven at part throttle operation. Such a condition definitely does not exist in conventional engines with a constant volume combustion chamber. After this optimal engine oil pressure was once set, no further adjustment of the engine oil pressure would be necessary unless a change in the grade of fuel were made by the operator.

What I claim that is new and useful in my invention is:

In an internal combustion engine there is provided an accessory cylinder opening into each combination chamber, each such accessory cylinder being closed at its distal end, said cylinder containing a control piston which is closed at both ends, said control piston serving to seal a space at the distal end of said accessory cylinder, said sealed space being filled with engine lubricating oil and called the hydraulic chamber; said hydraulic chamber being completely closed except for a minimal inlet orifice provided with a check-valve and a pressure relief valve; said pressure relief valve being of a hydraulic type; said hydraulic relief valve consisting of a diaphragm-like piston within a cylinder with means provided for the entrance of the engine lubricating oil to said cylinder, the lower portion of this piston being provided with a central small hemisphere-like protrusion to seal the escape orifice of, the hydraulic chamber and being also provided with a protrusion from the center of this hemisphere which passes through a guide within the escape orifice of the hydraulic chamber, said protrusion serving to maintain the alignment of the diaphragm-like piston of the hydraulic pressure relief valve, such a construction permitting low pressure oil on the large surface of the piston to exert a great force upon the small hemisphere of its opposite surface covering the escape orifice of the hydraulic chamber.

References Cited in the.file of this patent UNITED STATES PATENTS Re. 18,595 Wilson Sept. 13, 1932 1,386,144 Wall Aug. 2, 1921 2,142,621 Tsuneda Ian. 3, 1939 2,413,751 Dennis Jan. 7, 1947 2,769,433 Humphreys Nov. 6, 1956 

